The present invention relates generally to valves, and relates more specifically to a novel valve construction that provides many improved features over the prior art, and is well adapted for medical usage, such as in needleless IV sets, and other medical applications where it is desirable to avoid use of needles in the transmission and delivery of fluid products in a sterile environment.
Presently, there are many types of valves such as check valves which are designed to control the one-way flow of a fluid therethrough. One common type of check valve comprises a valve element, such as a ball or a spring biased valve stem, reciprocatingly positioned within a valve body providing a fluid passageway. The flow of fluid in one direction through the valve body is permitted upon displacement of the stem as it flows around the valve element to exit the valve body. However, in the opposite direction, the flow of fluid along with the spring forces the valve element against a valve seat, thereby inhibiting, or checking, the flow of fluid therethrough. In this manner, this type of check valve effectively provides that fluid can flow only in one direction through the check valve. An example of this type of valve can be found in U.S. Pat. No. 5,349,984.
Instead of necessitating fluid flow in an opposite direction in order to provide that the valve element is forced into the valve seat, some check valves provide means associated with the valve element for constantly urging the valve element into the valve seat. For example, a compression spring is often disposed within the valve body for this purpose. Because of the constant urging of the valve element into the valve seat by the compression spring, some amount of pressure must be exerted on the valve element to unseat same from the valve seat and allow fluid to flow therepast.
The check valves described above provide several disadvantages. For example, while the seating of the valve element in the valve seat provides that fluid cannot flow therepast, this does not provide that the end of the check valve body is sealed. As a result, bacteria or other contaminants may enter the valve body and accumulate in the valve body between the end of the valve body and the seated valve element. Additionally, often the valve element is disposed in the valve body some distance from the end of the valve body, therefore it may prove difficult to adequately clean or sterilize the check valve. In many applications, it is important to provide that the check valve is kept clean and sterile, such as in medical applications when, for example, fluid is being injected therethrough into a patient.
Moreover, in the case where a check valve is provided with a compression spring for urging the valve element into the valve seat, the fluid traveling through the check valve contacts the compression spring. In fact, fluid or other material on the other side of the check valve can contact the compression spring even when the valve element is seated in the valve seat. As a result, certain material can build up on the compression spring. For example, corrosion can build up on the compression spring over time, some metallic components can leach into the fluid, or, within a medical application, bacteria can build up on the compression spring. Because incoming fluid contacts the compression spring as the fluid flows through the check valve, the material which has built up on the compression spring may join the incoming fluid and flow out the check valve along with the incoming fluid. This is undesirable in most situations, and is especially undesirable within medical applications where sterility is a priority. Check valves in the medical field often provide even more areas at which bacteria can collect.
Furthermore, in medical applications, it is usually desirable to restrict exposure to the fluid being injected or extracted from the patient, and insulate nurses and doctors from exposure to said liquid. However, often the instrument used to inject or withdraw the fluid retains some of the fluid on the tip thereof, thus providing a risk to nurses and doctors of being exposed to the fluid.
The present invention is directed to address the problems encountered heretofore which are discussed hereinabove.